'-tos' definitions:
Definition of '-tos'
From: GCIDE
- Vigesimo-quarto \Vi*ges"i*mo-quar"to\, n.; pl. -tos. A book composed of sheets each of which is folded into twenty-four leaves; hence, indicating more or less definitely a size of book so made; -- usually written 24mo, or 24[deg]. [1913 Webster]